Flare cartridge

ABSTRACT

A simplified bore safe cartridge flare comprising a cartridge case configured for muzzle loading which may be easily manufactured by modern production methods allowing greater tolerance of dimensions with increased safety and reliability.

iiiiiie Males aie Froehner Jan. 1, 1974 [5 FLARE CARTRIDGE 3,068,756 12/1962 Schermuly 102 374 7 7 l [75] Inventor: Warren P. Froehner, China Lake, 2 969 Buss at a] Calif.

[73] Assignee: The United States of America as Primary Examiner Robert Stab] represented by the Secretary of the Atmmey R s Sciascia et Navy, Washington, DC.

[22] Filed: Sept. 14, 1972 21 A l. N 289 201 l 1 pp 0 57 ABSTRACT [52] US. Cl 102/32, 102/35.6, l02/37.6 51 11m. (:1 C0611 1/00 A slmpllfied bore Safe carmdge flare comprlsmg a {58] Field of Search lO2/37.8, 37.4, 32, "idge Case Configured for muzzle loading which may [02/39, 90' 40 37.6. 39/15 be easily manufactured by modern production methods allowing greater tolerance of dimensions with inl56] References cited creased safety and reliability.

UNITED STATES PATENTS 3,587,468 6/1971 Bliss 102/32 2 Claims, 6 Drawing Figures PAIENTEDJAM 1 I914 SHEET 2 BF 2 Fig. 4

FLARE CARTRIDGE CROSS-REFERENCES TO RELATED APPLICATIONS The present invention pertains to a cartridge flare of the type disclosed in assignees prior application Ser. No. 766,039, filed Oct. 4, 1968 and Ser. No. 155,090, filed Jun. 21, I971, now US. Pat. No. 3,712,224.

BACKGROUND OF THE INVENTION The present invention relates to a cartridge type flare and particularly to a cartridge flare for aerial delivery from a multiple cartridge dispenser by electric ignition means. The flare must be bore safe and reliable at high altitudes and at super sonic speeds.

Previously disclosed flare cartridge designs were complex and involved many parts and with some portions requiring plural manufacturing steps involving close tolerancing of parts. The prior art flare designs have not, therefore, been suitable for quantity production by modern techniques. Also, the prior art case design did not allow muzzle loading. Breech loading required the case to be in two parts necessitating at least one additional assembly step.

According to the present invention the cartridge case is easily manufactured in one piece by deep drawing, extrusion or rolling techniques and the case may be muzzle loaded with the necessary reduction in bore size at the muzzle being accomplished by a crimping operation. With this configuration all parts may be placed through the muzzle of the flare case and the crimped reduction at the muzzle has been found to provide the desired retention of the expelling piston to accomplish flare ignition as the flare grain clears the muzzle of the case.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a side elevational view partly in section of a flare arrangement according to the inventions;

FIG. 2 is an enlarged detail view of the igniter cap of the FIG. 1 device;

FIG. 3 is an enlarged end view of the piston in FIG. 1; and

FIGS. 4 through 6 are cross-sectional views similar to FIG. 1 showing the sequence of events following ignition.

l- DESCRIPTION AND OPERATION A flare system 10 is depicted in FIG. 1 wherein a flare 12 is contained along with other flares (not shown) in a launcher 14. The flares 12 are held in place in the launcher 14 by a cover member 16 which carries a plurality of impulse cartridges 18.

The flare 12 comprises a case 20 inclosing a flare grain 22 between an expelling piston 24 and an end clo sure 26. The piston 24 is sealed by a sheet of aluminum foil 28 and is fitted with an obturation seal 30. The aluminum foil 28 protects the parts within the flare casing on the after end while the closure 26 affords protection on the forward end. A spacer 32 of felt or other similar material is advantageously placed under closure 26 to take up tolerance variations. After placement of end closure 26, the case is crimped as shown at 34.

The clearances between the flare grain 22 and the case 20 and the degree of crimp at 34 are such that the flare grain 22 may be easily expelled from the casing through the crimped portion 34. The clearance between the walls of piston 24 and the casing 20, however, are such that the piston 24 will be reliably arrested by the crimp 34 for purposes which will become apparent in the following description of the ignition mechanism.

The ignition means comprises a piston 24 See FIGS. 1 and 3 having an extension 25 with a central bore 38 on the forward side and four circular openings 36 on the after side communicating in part with said bore 38. The piston 24 is fitted in the casing 20 with close tolerance and carries an obturating O-ring 30 to prevent passage of gases around the piston. The openings 36 are sealed with a sheet 28 of aluminum foil or the like cemented to or otherwise sealingly engaging the after side of piston 24.

A pellet cup 40(FIGS. 1 and 2)is cemented or otherwise fastened in a cavity 41 in flare grain 22 concentric with the extension 25 of piston 24. Cup 40 is provided with a centrally located flanged post 42 upon which is consolidated a pyrotechnic ignition mix 44. Cup 40 and extension 25 fit together with an O-ring therebetween.

Upon ignition of the expelling charge 18, gases therefrom immediately impinge upon seal 28 and piston 24. The seal 28 is broken at the opernings 36 and burning material from 18 enters chamber 38 to ignite pyrotechnic mix 44.

As shown in FIG. 4 ignition has just occured as described above. In FIG. 5 the hot gases impinging on piston 24 have urged flare grain 22 half way out of case 20. Pyrotechnic ignition pellet 44 has begun to burn but flare candle 22 has not been ignited. In FIG. 6 the piston 24 has reach the crimped portion 34 of case 20 and forward motion of the piston has been arrested. The flare grain 22 carrying cup 40 has cleared the muzzle of case 20, cup 40 has separated from piston extention 25 and fire from ignition pellet 44 now reaches the base of flare grain 22.

I claim:

1. In a bore safe flare system wherein a flare candle is adapted to be ignited only after it is expulsed from a housing by an explosive charge, the improvement comprising:

said housing consisting of a cylindrical case with a uniform central bore adapted for muzzle loading of flare components;

a flare candle in said casing;

a piston in said casing rearwardly of said flare grain; ignition means fastened in the after end of said flare candle and extending into a portion of said piston;

said piston and said ignition means being interfitted such that separation thereof must take place before ignition may be accomplished;

closure means in the forward end of the said casing and being fastened therein by slightly crimping the forward end of said casing and said crimping being sufficient to stop said piston for separation from said ignition means when said flare system is actuated.

2. The flare system improvement according to claim 1 further including:

said piston including a reduced forwardly extending hollow cylindrical portion and having a plurality of passages rearwardly of said hollow cylindrical portion and communicating therewith and rupturable closure means covering the after end of said piston, sealing said passageways. 

1. In a bore safe flare system wherein a flare candle is adapted to be ignited only after it is expulsed from a housing by an explosive charge, the improvement comprising: said housing consisting of a cylindrical case with a uniform central bore adapted for muzzle loading of flare components; a flare candle in said casing; a piston in said casing rearwardly of said flare grain; ignition means fastened in the after end of said flare candle and extending into a portion of said piston; said piston and said ignition means being interfitted such that separation thereof must take place before ignition may be accomplished; closure means in the forward end of the said casing and being fastened therein by slightly crimping the forward end of said casing and said crimping being sufficient to stop said piston for separation from said ignition means when said flare system is actuated.
 2. The flare system improvement according to claim 1 further including: said piston including a reduced forwardly extending hollow cylindrical portion and having a plurality of passages rearwardly of said hollow cylindrical portion and communicating therewith and rupturable closure means covering the after end of said piston, sealing said passageways. 